Assignee of the present invention previously proposed in Patent Document 1 a negative electrode for a nonaqueous secondary battery having a pair of current collecting surface layers of which the surfaces are brought into contact with an electrolyte and an active material layer interposed between the surface layers. The active material layer contains a particulate active material having high capability of forming a lithium compound. A metallic material having low capability of forming a lithium compound is present over the whole thickness of the active material layer such that the active material particles exist in the penetrating metallic material. Owing to the structure of the active material layer, even if the active material particles pulverize as a result of repeated expansion and contraction accompanying charge and discharge cycles, there is less likelihood of the particles falling off the negative electrode. Thus, the proposed negative electrode provides the advantage of an extended battery life.
In order for the particles in the active material layer to successfully absorb and release lithium ions, it is necessary to allow a nonaqueous electrolyte containing lithium ions to pass through the active material layer smoothly. For this, it is advantageous to provide paths through which a nonaqueous electrolyte can be supplied in the active material layer. Nevertheless, formation of too many flow passages reduces the effect of the metallic material in holding the particulate active material, which can allow the active material particles pulverized as a result of expansion and contraction accompanying charge and discharge cycles to fall off. Conversely, where formation of the flow passages is insufficient, the lithium ions are hardly allowed to reach inside the active material layer, and it would be limited to the active material particles existing on, and in the vicinity of, the surface of the active material layer that can take part in electrode reaction. As a result, the battery will have a reduced cycle life. The negative electrode disclosed in Patent Document 1 cited supra sometimes has insufficient voids in its active material layer, showing a tendency to have non-uniform passage of a nonaqueous electrolyte therethrough.    Patent Document 1 US 2006-115735A1
Accordingly, an object of the invention is to provide a negative electrode for a nonaqueous secondary battery with further improved performance over the above-described conventional technique.